Physical mechanisms for the dominant summertime high-latitude atmospheric teleconnection pattern and the related Northern Eurasian climates

Abstract

Summertime atmospheric teleconnection patterns over Eurasia have a significant influence on regional weather and climate. Despite extensive studies on the subtropical patterns, the high-latitude counterpart has received relatively less attention. This study proposes physical mechanisms for the formation and maintenance of the dominant high-latitude teleconnection pattern. The formation of the pattern is associated with variability in synoptic-scale eddy activity due to the meridional gradient of sea surface temperature anomalies in the vicinity of the Gulf Stream, causing a meridional shift of the central axis of storm track at the exit of Atlantic jet. The resultant convergence of transient vorticity fluxes to the west of the British Isles induces low-frequency cyclonic circulation anomalies and continued propagation of Rossby waves downstream along northern Eurasia. Once these circulation anomalies are formed, the subsequent latent heat-related diabatic anomalies over the northern Eurasian landmass act as another source of Rossby waves to maintain the teleconnection pattern. Regional temperature and precipitation variability is closely linked to the wave pattern along a route through northern Eurasia, and even precipitation over the East Asian summer monsoon region is influenced by the teleconnection pattern.

The Unprecedented 2023 North China Heatwaves and Their S2S Predictability

“…This wave train (Figure S8–S10 in Supporting Information ) is equivalent barotropic and shares striking similarities to the recently identified British–Baikal Corridor (BBC) pattern (Xu et al., 2019; Xu, Wang, Chen, et al, 2020). The BBC pattern is the dominant waveguide teleconnection pattern along the polar front jet and has been identified as the most important large‐scale circulation pattern driving the heatwaves over northern Eurasia (Kim & Seo, 2023; Li et al., 2021; Wang & Xu, 2024; Xu, Wang, Vallis, et al., 2021). The unprecedented 2019 heatwave in central Europe is a prominent example of the BBC pattern in forming extreme heat events (Xu, Wang, Liu, et al., 2020).…”